Process for preparing esters

ABSTRACT

A PROCESS FOR PREPARING ESTERS WHICH INVOLVES REACTING A DIBASIC ORGANIC ACID WITH ORGANIC HALIDE IN ADDED WATER CONTAINING A SULFONIC ACID HAVING FROM 12 TO 20 CARBON ATOMS.

United States Patent 3,686,275 PROCESS FOR PREPARING ESTERS Russell G. Hay, Gibsonia, and John G. MeNulty and William L. Walsh, Glenshaw, Pa, assignors to Gulf Research & Development Company, Pittsburgh, Pa. No Drawing. Filed Apr. 20, 1970, Ser. No. 30,244

int. Cl. C07e 69/34, 69/80 US. Cl. 260-475 R 17 Claims ABSTRACT OF THE DISCLOSURE A process for preparing esters which involves reacting a dibasic organic acid with an organic halide in added water containing a sulfonic acid having from 12 to 20 carbon atoms.

This invention relates to a process for preparing esters.

In application Ser. No. 333,624, filed Dec. 26, 1963, William L. Walsh discovered that monobasic organic acids could be reacted with selected organic halides to produce esters. Dibasic acids were not shown to be operative therein. In our application Ser. No. 845,080, filed July 25, 1969, we found that when monobasic organic acids were reacted with organic halides in added water, increased yields of esters were obtained and that dibasic organic acids could also be made to react with organic halides to produce esters, provided the reaction was carried out in the presence of added water. Unfortunately, while dibasic organic acids were made to react with organic halides in the presence of added water in said application Ser. No. 845,080, the amount of ester produced was small. We have now found that when the process in said latter application is carried out in the presence not only of added water but also a sulfonic acid having from 12 to 20 canbon atoms, increased amounts of desired ester are obtained.

The first reactant employed herein to produce the desired ester are dibasic acids that include dibasic organic acids such as aliphatic straight and branched chain dibasic acids having from four to 22 carbon atoms, preferably from four to 18 carbon atoms, straight and branched chain olefinic dibasic acids having from four to 22 carbon atoms, preferably from four to 18 carbon atoms, cyclic dibasic acids having from five to 22 carbon atoms, preferably from five to 18 carbon atoms, and aromatic dibasic acids having from eight to 22 carbon atoms, preferably from eight to 18 carbon atoms; and polybasic acids having from four to 22 carbon atoms, preferably from four to 18 carbon atoms. Specific examples of dibasic acids that can be employed include aliphatic straight and branched dibasic acids, such as succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, methylsuccinic acid, dimethylsuccinic acid, methyladipic acid, etc.; straight and branched olefinic dibasic acids, such as maleic acid, fumaric acid, methylmaleic acid, dimethylmaleic acid, ethylmaleic acid, meth ylfumaric acid, dimethylfumaric acid, chloromaleic acid, dichloromaleic acid, glutaconic acid, etc.; cyclic dibasic acids, such as cyclohexane dicarboxylic acid, cyclopentane dicarboxylic acid, cyclododecane, dicarboxylic acid, etc.; aromatic dibasic acids, such as ortho-phthalic acid, nitrophthalic acid, tetrachlorophthalic acid, etc., and polybasic acids, such as tricarballylic acid, aconitic acid, citric acid, etc.

To react with the dibasic acids defined above to produce the desired ester in accordance with the process defined and claimed herein there must be employed an organic halide selected from the group consisting of primary straight and branched chain alkyl halides having from one to 30 carbon atoms, preferably from one to 22 carbon atoms; secondary straight and branched chain alkyl halides having from one to 30 carbon atoms, preferably from one to 22 carbon atoms; primary cyclic halides having from four to 22 carbon atoms, preferably from four to 12 carbon atoms; secondary cyclic halides having from three to 22 carbon atoms, preferably from three to 12 carbon atoms, primary straight and branched chain olefinic halides having from three to 22 carbon atoms, preferably from six to 22 carbon atoms; and secondary straight and branched chain olefinic halides having from three to 22 carbon atoms, preferably from six to 22 carbon atoms. Specific examples of organic halides that can be used herein are the same as those defined in application Serial No. 333,624, referred to above, starting on page 4, line 21 thereof and ending on page 18, line 16, which organic halides are incorporated herein by reference. Of the organic halides defined above, we prefer to employ alkyl halides, particularly primary straight and branched chain alkyl halides. Of the alkyl halides, we prefer alkyl chlorides and alkyl bromides. Although we prefer to employ the organic acids and the organic halides in approximately stoichiometric amounts, the molar proportions thereof can vary from about 10:1 to about 1: 10.

As pointed out above in order that the dibasic acid be made to react with the organic halide herein water must be added to the reaction system. The molar ratio of water to the organic halide reactant defined above can be from about 1:1 to about :1, but preferably is about 2:1 to about 40:1.

Also needed in the reaction zone to increase yields of desired ester is a sulfonic acid having from 12 to 20 carbon atoms, preferably from 14 to 1-8 carbon atoms. Specific examples of sulfonic acids that can be employed are normal decylbenzenesulfonic acid, normal dodecylbenzenesulfonic acid, normal nonylbenzenesulfonic acid, normal octylbenzenesulfonic acid, normal heptylbenzenesulfonic acid, normal hexylbenzenesulfonic acid, normal tridecylsulfonic acid, normal tetradecylbenzene sulfonic acid, normal dodecanesulfonic acid, normal tridecanesulfonic acid, normal tetradecanesulfonic acid, normal pentadecanesulfonic acid, normal hexadecanesulfonic acid, normal heptadecanesulfonic acid, normal octadecanesulfonic acid, normal nonadecanesulfonic acid, normal eico sanesulfonic acid, 3-methyldodecanesulfonic acid, 3-methyl-S-ethyldecanesulfonic acid, 3-methyldecylbenzenesulfonic acid, 4-ethyloctylbenzenesulfonic acid, etc. By normal we mean linear. The amount of sulfonic acid required is at least about 0.05 percent by weight based upon the total reaction mixture, preferably from about 0.2 to about two percent by weight.

In carrying out the reaction, the reactants defined above, water and the defined sulfonic acid are merely brought together in any convenient manner. The temperature can be as low as about and as high as about 250 -C., but preferably is about to about 200 C. At the low temperatures, the reaction proceeds slowly, while at the higher temperatures shorter reaction times are required and the production of alcohols corresponding to the organic halide and some olefins and a slight increase in ether are obtained. Pressures are not critical and any pressure is suitable, but in order to maintain Water in the reaction zone, a pressure of at least about one hundred pounds per square inch gauge is preferred and pressures up to about 1000 pounds per square inch gauge can be used. The reaction time is similarly not critical and is dependent upon the other variables involved and on the amount of conversion desired. In general, a reaction time of about one minute to about 40 hours, preferably from about 15 minutes to about three hours can be used.

reaction with both phthalic acid and phthalic anhydride and obtained substantially similar results.

Obviously, many modifications and variations of the invention, as hereinabove set forth, can be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A process for preparing an ester which comprises contacting a dibasic organic acid selected from the group consisting of aliphatic straight and branched chain dibasic acids having from four to 22 carbon atoms, straight and branched chain olefinic dibasic acids having from four to 22 carbon atoms, cyclic dibasic acids having from five to 22 carbon atoms and aromatic dibasic acids having from eight to 22 carbon atoms with an organic halide selected from the group consisting of primary straight and branched chain alkyl halides having from one to 30 carbon atoms, secondary straight and branched chain alkyl halides having up to 30 carbon atoms, primary cyclic halides having from four to 22 carbon atoms, secondary cyclic halides having from three to 22 carbon atoms, primary straight and branched chain olefinic halides having from three to 22 carbon atoms and secondary straight and branched chain olefinic halides having from three to 22 carbon atoms in the presence of added water containing a sulfonic acid having from 12 to 20 carbon atoms.

2. The process of claim 1 wherein said dibasic acid is ortho phthalic acid.

3. The process of claim 1 wherein said dibasic acid is azelaic acid.

4. The process of claim 1 wherein said dibasic acid is adipic acid.

5. The process of claim 1 wherein said dibasic acid is maleic acid.

6. The process of claim 1 wherein said organic halide is l-bromo octane.

7. The process of claim 1 wherein said organic halide is l-bromo decane.

8. The process of claim 1 wherein said organic halide is l-chloro octane.

9. The process of claim 1 wherein the molar ratio of water to organic halide is from about 1:1 to about 1.

10. The process of claim 1 wherein the molar ratio of water to organic halide is from about 2:1 to about 40:1.

11. The process of claim 1 wherein said sulfonic acid is dodecylbenzenesulfonic acid.

12. The process of claim 1 wherein said sulfonic acid is a C -sulfonic acid.

13. The process of claim 1 wherein the amount of sulfonic acid present is at least about 0.05 percent by weight based upon the total reaction mixture.

14. The process of claim 1 wherein the amount of sulfonic acid present is from about 0.2 to about two percent by weight based upon the total reaction mixture.

15. The process of claim 1 wherein the reaction is carried out in a temperature range of about to about 250 C.

16. The process of claim 1 wherein the reaction is carried out in a temperature range of about to about 200 C.

17. The process of claim 1 wherein said dibasic acid is obtained from its corresponding anhydride.

References Cited UNITED STATES PATENTS 2,903,477 9/1959 Hughes et al 260475 LEWIS GOTTS, Primary Examiner E. J. SKELLY, Assistant Examiner U.S. Cl. X.R.

260-468 H, 468 K, 471 R, 475 N, 484 P, 485 R, 485 H, 485 L, 485 N CERTIFICATE Oreo Dated August 22, 1972 I Patent No. 275

InventOflS) Russell G. Hay John G. 'McNult and William L. Walsh It is certified that error appears in the above-identified patent I and that said Letters Patent are hereby corrected as shown below:

rj i Column 3, lines 10,11 and 12 of the middle column should read:

"stirred by a magnetic stirrer. The contents of the glass reactor were raised to reaction 1 temperature and pressured 100 to l50 pounds per square inch gauge."

Signed and sealed this 9th day of January 1973.

(SEAL) Attest:

ROBERT GOTTSCHALK Commissioner of. Patents EDWARD M.PLETCHER,JR. Attesting Officer 

